Question by StuwuStudio · Dec 05, 2015 at 10:52 PM · error mesh material meshfilter replace

Create multiple meshs in one mesh

Hi, I tried to create a "Screen" using Mesh and MeshFillter but when i create a new Mesh the last one is remove, i am very bad for explain, here is the code...

using UnityEngine; using System.Collections;

public class ScreenBoard : MonoBehaviour {

 public Transform ScreenObject;
 public Texture2D PixelsRed;
 public Texture2D PixelsBlue;
 public Texture2D PixelsGreen;
 public Texture2D PixelsBlack;
 public Texture2D PixelsWhite;
 public Texture2D PixelsYellow;
 public Texture2D PixelsOrange;
 public Texture2D PixelsMangenta;

 MeshFilter mf;
 Mesh mesh;
 MeshRenderer mr;

 int[,] ColorIdInt;

 //15w by 10h pixelscreen

 void ResetScreen() {
     ColorIdInt = new int[15,10];
     mf = ScreenObject.GetComponent<MeshFilter>();
     mesh = new Mesh();
     mr = ScreenObject.GetComponent<MeshRenderer>();
     mf.mesh = mesh;

 }

 void GetUpdate(float X, float Y, string ColorId) {
     int SaveX = Mathf.RoundToInt(X);
     int SaveY = Mathf.RoundToInt(Y);
     X = Mathf.RoundToInt(X);
     Y = Mathf.RoundToInt(Y);
     X = X * 0.1f;
     Y = Y * 0.1f;

     Vector3[] verticles = new Vector3[4] {
         new Vector3(X + 0, Y + 0, -0.01f), new Vector3( X + 0.1f, Y + 0, -0.01f), new Vector3(X + 0, Y + 0.1f, -0.01f), new Vector3(X + 0.1f, Y + 0.1f, -0.01f)
     };

     int[] tri = new int[6];

     tri[0] = 0;
     tri[1] = 2;
     tri[2] = 1;

     tri[3] = 2;
     tri[4] = 3;
     tri[5] = 1;

     mesh.vertices = verticles;
     mesh.triangles = tri;

     if(ColorId == "Red") {
         mr.material.mainTexture = PixelsRed;
         ColorIdInt[SaveX,SaveY] = 1;
     }
     if(ColorId == "Green") {
         mr.material.mainTexture = PixelsGreen;
         ColorIdInt[SaveX,SaveY] = 2;
     }
     if(ColorId == "Blue") {
         mr.material.mainTexture = PixelsBlue;
         ColorIdInt[SaveX,SaveY] = 3;
     }
     if(ColorId == "Black") {
         mr.material.mainTexture = PixelsBlack;
         ColorIdInt[SaveX,SaveY] = 4;
     }
     if(ColorId == "White") {
         mr.material.mainTexture = PixelsWhite;
         ColorIdInt[SaveX,SaveY] = 5;
     }
     if(ColorId == "Yellow") {
         mr.material.mainTexture = PixelsYellow;
         ColorIdInt[SaveX,SaveY] = 6;
     }
     if(ColorId == "Orange") {
         mr.material.mainTexture = PixelsOrange;
         ColorIdInt[SaveX,SaveY] = 7;
     }
     if(ColorId == "Magenta") {
         mr.material.mainTexture = PixelsMangenta;
         ColorIdInt[SaveX,SaveY] = 8;
     }
 }

 // Use this for initialization
 void Start () {
     ResetScreen();
     GetUpdate(1, 0, "Red");
     GetUpdate(2, 0, "Green");
 }
 
 // Update is called once per frame
 void Update () {

 }

}

First, i reset mesh of the screen, after, i execute the GetUpdate function. There, i get position of vertices and triangle, and, i assing them on my mesh (my problem: the new mesh replace the old one). After, i add the material. I hope you understand... sorry for bad english

Add comment · Show 10

Cherno · Dec 06, 2015 at 01:06 PM 0

Of course the mesh gets replaced, that what you tell thegame to do, after all, with these lines:

 mesh.vertices = verticles;
      mesh.triangles = tri;

What you can do is to convert toe mesh.vertices and mesh.triangles into a temporary list, then add the new vertices and triangles to it, and then assign those list back to the mesh via .ToArray().

StuwuStudio · Dec 06, 2015 at 08:03 PM 0

Thanks! It's work perfectly using list! But i have one problem; how to set a specific material for each "Pixel"? i know i need to use UVs and all that stuff? Do you have any pathway or hint?

(I'm a bite late, i'm busy)

Cherno StuwuStudio · Dec 07, 2015 at 08:17 PM 0

Each element in the UV array is a Vector2 which has the x,y coordinates of the corresponding vertex that has the same index in the vertices array as the Vector2 in the UV array. The x and y values go from 0 to 1 (values above that just repeat). They define a point on the texture image the material uses, typcially as the Diffuse/Albedo texture. For more information about UV mapping, you should read the entry in the User $$anonymous$$anual and Scripting API.

maccabbe StuwuStudio · Dec 07, 2015 at 10:22 PM 0

To use multiple materials you would typically use a mesh with submeshes and a renderer with multiple materials. RIght now you are using mesh.triangles and renderer.material. This is equivilant to using the first submesh, mesh.GetTriangles(0) and the first material in the materials, renderer.materials[0], So to use a second submesh you would set the number of submeshes, use mesh.SetTriangles(int) to set the submesh, and set rendererer,materials to have more elements. i.e.

 var filter = GetComponent<$$anonymous$$eshFilter>();
 var mesh = new $$anonymous$$esh();
 mesh.sub$$anonymous$$eshCount = 2;
 mesh.vertices = vertices;
 mesh.SetTriangles(triangles1, 0);
 mesh.SetTriangles(triangles2, 1);
 filter.mesh = mesh;
 
 var renderer = GetComponent<$$anonymous$$eshRenderer>();
 renderer.materials = new $$anonymous$$aterial[2]{material1, material2};

http://docs.unity3d.com/ScriptReference/$$anonymous$$esh-sub$$anonymous$$eshCount.html

http://docs.unity3d.com/ScriptReference/$$anonymous$$esh.SetTriangles.html

http://docs.unity3d.com/ScriptReference/Renderer-materials.html

http://docs.unity3d.com/ScriptReference/$$anonymous$$esh.html

StuwuStudio · Dec 07, 2015 at 10:47 PM 0

Uh... I understand uvs but there my (last) problem, after assing UVs and "divise" triangle of the mesh, i don't know how to assing the material to the triangles. Here's my script and i hope you help me to fix the last problem :) I put just the render/mesh thing of the script

 public $$anonymous$$aterial[] mats;
 List<Vector2> uvs;

 $$anonymous$$eshFilter mf;
 $$anonymous$$esh mesh;
 $$anonymous$$eshRenderer mr;

...

     Vector2[] uv = new Vector2[4];

     uv[0] = new Vector2(0,0);
     uv[1] = new Vector2(1,0);
     uv[2] = new Vector2(0,1);
     uv[3] = new Vector2(1,1);

     foreach(Vector2 SingleUV in uv) {
         uvs.Add(SingleUV);
     }

     mesh.uv = uvs.ToArray();
     mesh.RecalculateNormals();
     mesh.sub$$anonymous$$eshCount = (triangles.Count / 6);

     mf.mesh.SetTriangles(new int[] {
         vertices.Count + 0,
         vertices.Count + 2,
         vertices.Count + 1,

         vertices.Count + 2,
         vertices.Count + 3,
         vertices.Count + 1,
     }, triangles.Count / 6));

     mr.material = mats;

StuwuStudio · Dec 08, 2015 at 01:00 AM 0

I check on web and i found sub mesh. How to use it?

maccabbe StuwuStudio · Dec 08, 2015 at 03:09 AM 0

The script I attached should be a good start.

Submeshes are different sets of triangles for one mesh, you were actually using the first submesh when you did mesh.triangles=triangles. The exact same thing should happen if you did mesh.SetTriangles(triangles, 0).

If you change sub$$anonymous$$eshCount to 2 then you can define the second submesh (i.e. mesh.SetTriangles(triangles2, 1) which means you'd have two submeshes. If your renderer has 2 materials then the first submesh will automatically use the first material and the second submesh will use the second material.

StuwuStudio maccabbe · Dec 08, 2015 at 10:39 PM 0

ANOTHER PROBLE$$anonymous$$ WHICH IS NOT ON WEB: Failed setting triangles. Some indices are referencing out of bounds vertices.

StuwuStudio · Dec 08, 2015 at 12:43 PM 0

Great! But, can and how i edit sub-mesh? Did i need to use (Again :P) a list? I currently working on.

Show more comments